![Page 1: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/1.jpg)
Acceleration
![Page 2: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/2.jpg)
Velocity-Time Graphs
A graph that plots an object’s velocity versus the time.
The rate at which an object’s velocity is changing is called acceleration and can be found by calculating the slopeof the velocity-time graph.
![Page 3: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/3.jpg)
Example Graph
![Page 4: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/4.jpg)
Facts about acceleration: Acceleration is the change in velocity divided
by the time it takes to make that change. It is possible to have positive or negative
acceleration as well as acceleration equal to zero.
Acceleration is a vector quantity with the SI unit of m/s2, pronounced “meters per second squared.”
A change in direction will cause a change in velocity, so it will cause acceleration.
![Page 5: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/5.jpg)
Acceleration Possibilities (there are 9)
![Page 6: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/6.jpg)
If initial velocity is zero… 3 possibilites
vi= 0 and a = 0:The object is at rest and remains at rest
vi= 0 and a = positive:The object is at rest and begins to move forward with increasing speed.
vi= 0 and a = negative:The object is at rest and begins to move backward with increasing speed.
![Page 7: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/7.jpg)
vi= positive and a = negative: The object is moving in a forward direction and is decreasing speed.
vi= positive and a = 0: The object is moving in a forward direction at a constant speed.
vi= positive and a = positive: The object is moving in a forward direction and is increasing speed.
If initial velocity is positive… 3 possibilities
![Page 8: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/8.jpg)
vi= negative and a = negative: The object is moving in a backward direction and is increasing speed.
vi= negative and a = 0: The object is moving in a backward direction at a constant speed.
vi= negative and a = positive: The object is moving in a backward direction and is decreasing speed.
If initial velocity is negative… 3 possibilites
![Page 9: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/9.jpg)
Calculating Average Acceleration
a v
t(v f vi)
t
This formula is cannot fit into any “magic triangle”, so we have to learn it the regular way.
![Page 10: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/10.jpg)
Example Problem 1
Describe the motion of the object represented in this graph:
![Page 11: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/11.jpg)
From 0 to 5.0 s: Speeds up from rest at a constant rate
From 5.0 to 10.0s: Remains at a constant speed of 30.0m/s
From 10.0 to 15.0s: Decreases in speed from 30 to 20m/s
From 15.0 to 20.0s: Remains at a constant speed of 20m/s
From 20.0 to 25.0s: Comes to a stop
![Page 12: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/12.jpg)
Example Problem 2
Find the uniform acceleration that causes a car’s velocity to change from 32 m/s to 96 m/s in an 8.0-s period.
![Page 13: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/13.jpg)
Example Problem 2 Picture
a = ?
t = 8.0s
vi = 32m/s vf = 96m/sNotice how
every number
in the problem
is represented
in the picture!
![Page 14: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/14.jpg)
Example Problem 2 work
a = vf = vi = t =
Fill in the
left-hand
line up!
![Page 15: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/15.jpg)
Example Problem 2 work
a = ? vf = 96 m/s vi = 32 m/s t = 8.0s
a (v f v i)
t
a (96m /s 32m /s)
8.0s
a 64m /s
8.0s 8.0m /s2
![Page 16: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/16.jpg)
Example Problem 3
A car with a velocity of 22 m/s is accelerated uniformly at the rate of 1.6 m/s2 for 6.8 s. What is its final velocity?
![Page 17: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/17.jpg)
Example Problem 3 picture
a = 1.6m/s2
t = 6.8s
vi = 22m/s vf = ?
![Page 18: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/18.jpg)
Example Problem 3 work
a = vf = vi = t =
Fill in the
left-hand
line up!
![Page 19: Acceleration · 2015. 9. 2. · Facts about acceleration: Acceleration is the change in velocity divided by the time it takes to make that change. It is possible to have positive](https://reader035.vdocuments.site/reader035/viewer/2022063023/5ffe7bf7a2ea8d3933043652/html5/thumbnails/19.jpg)
Example Problem 3 work
a = 1.6 m/s2
vf = ? vi = 22 m/s t = 6.8 s
a (v f v i)
t at v i v f
(6.8s)(1.6m /s2) 22m /s v f
32.88m /s v f
33m /s v f